EP0618352B1 - Poussoir hydraulique - Google Patents

Poussoir hydraulique Download PDF

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Publication number
EP0618352B1
EP0618352B1 EP94302313A EP94302313A EP0618352B1 EP 0618352 B1 EP0618352 B1 EP 0618352B1 EP 94302313 A EP94302313 A EP 94302313A EP 94302313 A EP94302313 A EP 94302313A EP 0618352 B1 EP0618352 B1 EP 0618352B1
Authority
EP
European Patent Office
Prior art keywords
tappet
oil
hydraulic
valve
cam
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94302313A
Other languages
German (de)
English (en)
Other versions
EP0618352A2 (fr
EP0618352A3 (fr
Inventor
Keiji Guroriasu Chiryu 3 704 Kawasaki
Shinichi Miwa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NGK Insulators Ltd
Original Assignee
NGK Insulators Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NGK Insulators Ltd filed Critical NGK Insulators Ltd
Publication of EP0618352A2 publication Critical patent/EP0618352A2/fr
Publication of EP0618352A3 publication Critical patent/EP0618352A3/fr
Application granted granted Critical
Publication of EP0618352B1 publication Critical patent/EP0618352B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
    • F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
    • F01L1/245—Hydraulic tappets
    • F01L1/25—Hydraulic tappets between cam and valve stem
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/14—Tappets; Push rods
    • F01L1/143—Tappets; Push rods for use with overhead camshafts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2301/00—Using particular materials
    • F01L2301/02—Using ceramic materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2101—Cams
    • Y10T74/2107—Follower

Definitions

  • the present invention relates to a tappet for a valve mechanism for an internal combustion engine, for example, an engine for an automobile, and more particularly to a hydraulic tappet capable of improving the efficiency of the engine for an automobile.
  • An internal combustion engine such as an engine for an automobile, has a tappet or a rocker arm disposed at an end of a valve shaft to transmit the kinetic force of a cam to a valve mechanism.
  • Thermal expansion or thermal shrinkage of a cylinder head or a valve occurring at the time of the operation and incomplete seating of the valve occurring due to wear of the valve or a valve seat are prevented and the kinetic characteristics of the valve system are improved by disposing a hydraulic or mechanical adjustment mechanism at the location at which the tappet or the rocker arm is in contact with the end of the valve shaft.
  • Fig. 3 illustrates an example of a conventional tappet 10 of a hydraulic adjustment type. If a cylinder head (omitted from the illustration) or a valve 18 undergoes thermal expansion or thermal shrinkage, the hydraulic pressure in an oil reservoir 16 disposed in the metal tappet 10 is used to adjust the position of the spring portion of the tappet for pressing the valve so that the transmission characteristics from a cam 17 are compensated.
  • an upwardly projecting annular flange 20 of the base wall of the tappet receives a cup-shaped member 21 which is fixed on the end of the stem or push-rod of the valve 18.
  • a sliding piston member 22 upwardly biased by a spring 23.
  • a conventional tappet of the foregoing hydraulic adjustment type involves generation of excessively large frictional force when the cam 17 slides on the cam sliding surface 12 of the metal tappet 10 as shown in Fig. 3.
  • the crankshaft must bear an excessively heavy load, and therefore the efficiency of the engine deteriorates.
  • the employed mechanism in which oil is enclosed in the tappet, means that the oil reservoir occupies a large part of the inside of the tappet, and the weight of the tappet is increased excessively, so that the transmission loss occurring due to the vertical motion of the valve 18 is large.
  • EP-A-225 096 describes a tappet of the general type shown in Fig. 3. It is suggested that ceramic materials or cermets may be employed for the tappet.
  • the present invention is directed to overcome the foregoing problems experienced with the conventional technology, and therefore an object of the same is to provide a hydraulic tappet capable of efficiently using the force transmitted from the crank shaft, therefore reducing the transmission loss and improving the efficiency of the engine.
  • the present invention provides a hydraulic tappet for a valve mechanism of an internal combustion engine, as set forth in claim 1.
  • the cam sliding portion, the skirt portion and the spring holding portion of the hydraulic tappet are made of a ceramic material. Therefore, the total weight of the tappet can be reduced, and the ratio of the power loss occurring during transmission from the crank shaft can be lowered so that the transmission characteristics can be improved.
  • the cam sliding portion is made of a ceramic material exhibiting superior sliding characteristics to those of metal hitherto used enables the frictional force between a cam and the cam sliding portion, which is generated when the cam is rotated, to be reduced.
  • the oil supply port is formed in the side wall of the tappet to supply oil from outside and oil is reserved in the spring holding portion.
  • the proportion of the oil reservoir occupying the tappet can significantly be lowered, compared with the structure of Fig. 3. Therefore, the total weight of the tappet can be reduced to about two-third to half of that of the conventional tappet, and accordingly the transmission characteristics from the crank shaft can be improved so that the efficiency of the engine can be improved.
  • the supply and refreshment of oil in the spring-holding portion can take place during operation, from the oil around the tappet in the engine. This changing of the oil increases the life of the tappet compared with the tappet of Fig. 3.
  • Fig. 1 is a cross-sectional view which illustrates an embodiment of a hydraulic tappet according to the present invention.
  • Fig. 2 is a cross-sectional view which illustrates another embodiment of a hydraulic tappet according to the present invention.
  • Fig. 3 is a cross-sectional view which illustrates a conventional hydraulic adjustment type tappet.
  • Fig. 1 is a cross-sectional view which illustrates an example of a hydraulic tappet according to the present invention.
  • the hydraulic tappet 1 has a cam sliding portion 2, a skirt portion 3 and a spring holding portion 4, all of which are made of ceramic, resulting in weight reduction compared with a structure in which they are made of metal. Since ceramic can exhibit excellent sliding characteristics, the frictional force can significantly be reduced between the cam sliding portion 2 and a cam (omitted from Fig. 1). As a result, the efficiency of the engine can be improved.
  • the type of the ceramic material to be employed is not limited particularly, it is exemplified by Si 3 N 4 and sialon. In particular, Si 3 N 4 exhibits excellent friction characteristics with chilled cast iron, which is the material of the cam, and is preferably employed.
  • an oil supply port 5 is formed as a conduit between the skirt portion 3 and the spring holding portion 4 to be supplied freely with oil from outside as the tappet 1 is operated and that oil is held in only the spring holding portion 4.
  • the spring holding portion 4 which is an annular skirt projecting downwardly from the top wall of the tappet acts to guide and hold the parts 21,22,23 (shown in Fig. 3 and omitted from each of Figs. 1 and 2) and serves as an oil reservoir.
  • the tappet therefore has the same hydraulic adjustment function as the tappet of Fig. 3. Pressure is maintained as required in the oil reservoir due to the oil pressure outside the narrow bore of the port 5.
  • this embodiment has the arrangement that only the spring holding portion 4 serves as the oil reservoir and oil required is supplied from outside, so that the oil is changed during operation.
  • the size of the oil reservoir can be reduced, and therefore the total weight of the tappet can be reduced in addition to the weight reduction realized by the ceramic material.
  • the oil change increases the life of the tappet. Therefore, the efficiency of the engine can further be improved.
  • the tappet 1 is made of ceramic, excellent heat resistance and corrosion resistance can be exhibited as compared with the conventional hydraulic tappet.
  • An integrated-structure ceramic tappet can easily be manufactured by an injection molding method or a slip casting method or the like. Further, it can be shaped into a nearly final shape which requires substantially no time in the machining after forming.
  • Fig. 2 illustrates another example of the hydraulic tappet according to the present invention.
  • the oil supply port 5 is formed of a metal pipe.
  • a ceramic usually requires a great many processes to be manufactured and machined in detail, for example, forming an aperture, the arrangements that the oil supply port 5 is formed of the metal pipe facilitates machining. Therefore, the cost can be reduced.
  • the metal pipe can easily be connected to the body of the ceramic tappet by press-fitting or brazing. Further, the weight can be reduced in this case as compared with the conventional arrangement that the tappet is fully made of metal material.
  • Fig. 2 shows that there is a slot 2a in the top wall and side wall of the tappet; however the top of the spring holding portion 4 is closed.
  • the present invention has been described through the embodiments, the present invention is not limited to the foregoing embodiments.
  • the present invention can be applied to a variety of internal combustion engines as well as to the engine for an automobile. By combining it with a ceramic cam and/or a valve, the efficiency of the engine can further be improved.
  • an oil supply port is used and a ceramic material is used to form the tappet so that there can be provided a hydraulic tappet capable of efficiently using the motive power from the crank shaft, reducing the transmission loss and improving the efficiency of the engine.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Gears, Cams (AREA)

Claims (3)

  1. Poussoir hydraulique pour un mécanisme de soupape d'un moteur à combustion interne, ledit poussoir hydraulique comportant des éléments de composant sous la forme d'une portion de coulissement de came (2), d'une portion de rebord (3) et d'une portion de retenue de ressort (4) faisant saillie vers le bas en dessous de la portion de coulissement de came (2), où tous les trois desdits éléments de composant sont formés comme un corps céramique unitaire, et ladite portion de retenue de ressort (4) comporte un espace de retenue d'huile, caractérisé par un orifice d'amenée d'huile (5) qui s'étend depuis ledit espace de retenue d'huile de la portion de retenue de ressort (4) à ladite portion de bordure (3) pour réaliser un conduit pour l'huile, pour passer entre ledit espace de retenue d'huile et l'extérieur du poussoir.
  2. Poussoir hydraulique selon la revendication 1, où ledit orifice d'amenée d'huile (5) est un tube métallique.
  3. Poussoir hydraulique selon la revendication 2, où ledit tube métallique est disposé dans une fente (2a) ménagée dans le poussoir, la fente (2a) s'ouvrant vers la portion de coulissement de came (2) et la portion de bordure (3) du poussoir.
EP94302313A 1993-03-30 1994-03-30 Poussoir hydraulique Expired - Lifetime EP0618352B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5072577A JPH06280513A (ja) 1993-03-30 1993-03-30 油圧式タペット
JP72577/93 1993-03-30

Publications (3)

Publication Number Publication Date
EP0618352A2 EP0618352A2 (fr) 1994-10-05
EP0618352A3 EP0618352A3 (fr) 1995-01-11
EP0618352B1 true EP0618352B1 (fr) 1998-06-03

Family

ID=13493380

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94302313A Expired - Lifetime EP0618352B1 (fr) 1993-03-30 1994-03-30 Poussoir hydraulique

Country Status (4)

Country Link
US (1) US5572963A (fr)
EP (1) EP0618352B1 (fr)
JP (1) JPH06280513A (fr)
DE (1) DE69410677T2 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9732639B1 (en) 2015-10-20 2017-08-15 Anthony Dike Variable lift valve train

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2584138A1 (fr) * 1985-06-28 1987-01-02 Inst Francais Du Petrole Poussoir hydraulique comportant des parties ceramiques pour moteurs thermiques

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367701A (en) * 1979-12-05 1983-01-11 Eaton Corporation Acting valve gear
US4590898A (en) * 1979-12-05 1986-05-27 Eaton Corporation Hydraulic tappet for direct-acting valve gear
US4768476A (en) * 1981-02-20 1988-09-06 Stanadyne, Inc. Tappet with ceramic camface
US4715334A (en) * 1983-12-07 1987-12-29 Eaton Corporation Self contained hydraulic bucket lifter
US4688526A (en) * 1983-12-07 1987-08-25 Eaton Corporation Self-contained hydraulic bucket lifter
JPS60219407A (ja) * 1984-04-13 1985-11-02 Honda Motor Co Ltd 内燃機関の油圧タペツト装置
DE3500425A1 (de) * 1985-01-09 1986-07-10 Motomak Motorenbau, Maschinen- u. Werkzeugfabrik, Konstruktionen GmbH, 8070 Ingolstadt Hydraulischer tassenstoessel fuer verbrennungsmotoren
DE3529446A1 (de) * 1985-08-16 1987-02-26 Audi Ag Tassenstoessel mit hydraulischer einstellung
JPS62276206A (ja) * 1986-05-23 1987-12-01 Ngk Spark Plug Co Ltd バルブリフタ−
DE3704929A1 (de) * 1987-02-17 1988-08-25 Daimler Benz Ag Tassenstoessel mit hydraulischem spielausgleich
JPH01170704A (ja) * 1987-12-25 1989-07-05 Nippon Steel Corp タペット
DE3919777C1 (fr) * 1989-06-16 1990-06-21 Daimler-Benz Aktiengesellschaft, 7000 Stuttgart, De
DE3920729A1 (de) * 1989-06-24 1991-01-10 Gmb Giesserei & Maschinenbau B Tassenstoesselkoerper fuer ventilstoessel
US5320074A (en) * 1993-06-17 1994-06-14 Sealed Power Technologies Limited Partnership Direct acting hydraulic tappet

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2584138A1 (fr) * 1985-06-28 1987-01-02 Inst Francais Du Petrole Poussoir hydraulique comportant des parties ceramiques pour moteurs thermiques

Also Published As

Publication number Publication date
EP0618352A2 (fr) 1994-10-05
EP0618352A3 (fr) 1995-01-11
JPH06280513A (ja) 1994-10-04
US5572963A (en) 1996-11-12
DE69410677T2 (de) 1999-02-18
DE69410677D1 (de) 1998-07-09

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